I recall an interview with a brain researcher on NPR a couple years ago...perhaps one of the people you mention above. He and his team had found, through brain scans and various other tests, that the same part of the brain "lit up" by musical activity also seemed to be responsible for "the modulation of interpersonal space." For me, this explains why angst-ridden teenagers so consistently reach for guitars and/or musical media devices when dealing with relationship highs and lows... and why the rest of us ought to be employing music in all manner of relationships and social justice work.

Music-making is one of the most "functional" pursuits I know!